The given digits are 3, 6, 8 and 7. Here, 3 < 6 < 7 < 8 In order to form the largest three-digit number, we have to place digits 8, 7, and 6 at the hundreds, tens, and ones place, respectively. Thus, the required largest three-digit number is 876. Hence, the correct option is (5).

The given expansion is 8 x 10000000 + 8 x1000000 + 1 x 100000 + 4 x 10000 + 2 x 100 + 1 x1 = 8 crores + 8 ten lakhs + 1 lakh + 4 ten thousands + 2 hundreds + 1 ones = 88140201 Thus, the number 88140201is equivalent to the given expansion. Hence, option (1) is correct.

The given numbers are 2627, 8612, 8126 and 3716. When a set of numbers is arranged in descending order, the numbers are written in such a manner that the greatest number is placed at the beginning of the sequence; the second greatest number is placed after that and so on. The given numbers can be arranged in descending order as 8612 > 8126 > 3716 > 2627. Hence, option (3) is correct. 

The given digits are 6, 4, 5, and 9. Here, 4 < 5 < 6 < 9 We have to form a four-digit number such that digit 6 is always at the ones place. In order to form the greatest four-digit number, we have to place digits 9, 5, and 4 at the thousands, hundreds and tens place respectively and 6 at the ones place.  Therefore, the number so formed is 9546. Similarly, the smallest four-digit number will have 4 at the thousands place, 5 at the hundreds place, 9 at the tens place, and 6 at the ones place. The number so formed is 4596. Therefore, the smallest and the greatest numbers that can be formed by the digits 6, 4, 5 and 9 such that digit 6 is always at the ones place and no digit is repeated are 4596 and 9546, respectively. Hence, the required difference is 9546 - 4596 = 4950 The correct option is (4). 

The expression {(30 + 45) / 5} + {(18 - 3) x 20} can be solved by simplifying the brackets. {(30 + 45) / 5} + {(18 - 3) x 20} = {75 / 5} + {15 x 20} = 15 + 300 = 315  Hence, the value of the given expression is 315. The correct answer is option (1). 

Radhika's monthly salary in May = Rs. 13,500. 

Increase in salary = Rs. 2,150

Therefore, her current monthly salary can be obtained by adding Rs. 2,150 to Rs. 13,500.

Thus, her current monthly salary is Rs. 15,650.

The correct answer is option (2). 

It is known that 1 kg = 1000 g Therefore, 50 kg = 50 * 1000 g = 50,000 g  8 kg = 8 * 1000 g   = 8000 g 6 kg = 6 * 1000 g = 6000 g  9 kg = 9 * 1000 g = 9000 g Therefore, the correct answer is option (3).

The given Roman numerals are LVI and XCIV. LVI = L + VI = 50 + 6  [L = 50; VI = 6] = 56 XCIV = XC + IV = (100 - 10) + 4  [X = 10; C = 100; IV = 4] = 94 Therefore, LVI + XCIV = 56 + 94  = 150 The correct answer is option (3).

Since 20 > 6, the difference of 20 and 6 can be represented as (20 - 6). Accordingly, the multiplication of 39 with the difference of 20 and 6 can be represented as 39 x (20 - 6). Thus, the required expression is 39 x (20 - 6). The correct answer is option (4). 

The given Roman numerals are LV and XCIII. The first numeral can also be written as LV = L + V = 50 + 5      ..........[L = 50; V = 5]  = 55 The second numeral can also be written as XCIII = XC + III = (100 - 10) + 3      ................[X = 10; C = 100; III =3] = 93 Therefore, LV x XCIII = 55 * 93 = 5115 The correct answer is option (1).